ABSTRACT Background and Objectives: Apolipoprotein M (APOM) is a novel high-density lipoprotein (HDL)-associated protein involved in the production of pre-beta HDL and cholesterol efflux to HDL. The present study examined effect of 12 weeks of aerobic interval training on HDL-associated APOM levels.Methods: Study population included 20 healthy men aged 20 to 24 years. The subjects were randomly and equally divided into a training group and a control group. Each training session included 10 minutes of warm-up, 35 minutes of aerobic training (5 combined cycles each including four minutes of running at intensity of 85-95% and an active resting period of treadmill running at 65-75% of maximum heart rate for 3 minutes) and 10 minutes of cool-down. Blood samples (10 mL) were taken every four weeks. Two-way ANOVA and Bonferroni's post hoc test were used to compare the groups. A P-value of less than 0.05 was considered statistically significant. Results: At the end of the 12th week, HDL-associated APOM levels increased in the training group and decreased in the control group. However, these changes were not statistically significant (P>0.05). Conclusion: This study demonstrated that the 12-week aerobic interval training does not significantly affect HDL-associated APOM levels. However, it is recommended to monitor subjects’ diet throughout the study period to reach a more comprehensive conclusion. Keywords: Aerobic interval training, Apolipoprotein M, Young men.